An electrocardiogram (ECG or EKG, abbreviated from the German Elektrokardiogramm) is a graphic produced by an electrocardiograph, which records the electrical activity of the heart over time. Its name is made of different parts: electro, because it is related to electronics, cardio, Greek for heart, gram, a Greek root meaning "to write". Analysis of the various waves and normal vectors of depolarization and repolarization yields important diagnostic information.
It is the gold standard for the diagnosis of cardiac arrhythmiasBraunwald E. (Editor), Heart Disease: A Textbook of Cardiovascular Medicine, Fifth Edition, p. 108, Philadelphia, W.B. Saunders Co., 1997. ISBN 0-7216-5666-8.
It guides therapy and risk stratification for patients with suspected acute myocardial infarction"2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care - Part 8: Stabilization of the Patient With Acute Coronary Syndromes." Circulation 2005; 112: IV-8